It is well known to provide a passive seat belt wherein one belt end is mounted inboard the seat by a retractor and the other belt end is mounted on the door. Opening and closing movement of the door automatically winds and unwinds the belt between restraining and nonrestraining positions relative the seated occupant. It is characteristic of such a passive belt system that many layers of belt are wound upon the reel when the door is closed and the belt is in the restraining position. The prior art has provided various belt clamping mechanisms movably mounted on the retractor adjacent the exit of the belt from the reel and effective to clamp the belt against spooling down and extending from the reel after the reel is locked by an inertia sensor. For example, U.S. Pat. No. 4,120,466, issued Oct. 17, 1978 to Adomeit, disloses a self-actuated belt clamping device in which the belt is guided around the end of a lever so that imposition of an occupant restraint load on the belt pivots the lever to clamp the belt between a locking surface carried on the lever and a locking surface mounted on a fixed housing. U.S. Pat. No. 4,300,731 issued Nov. 17, 1981 to Joseph D. Kondziola provides a spindle mechanism which traverses a toothed rack upon onset of an occupant restraint load to roll-up and clamp the belt thereby preventing spool-out of the belt wound upon the reel.
It has been recognized in the prior art that the mounting of a restraint belt on the vehicle seat may require a system of anchoring the seat to the vehicle floor to prevent forward movement of the seat by the occupant restraint loads transmitted from the retractor to the seat. U.S. Pat. No. 4,109,962 issued Aug. 29, 1978 to Joseph J. Magyar discloses a reel mounted on the seat for winding and unwinding an anchor belt attached to the vehicle body floor rearward the seat. A reel locking pawl is actuated by the onset of an occupant restraint load to thereby lock the belt reel and fix the length of the anchor belt to restrain the seat and the belt attached thereto from forward movement. U.S. Pat. No. 4,264,091, issued Apr. 28, 1981 to David N. Lee, discloses the use of an inertia locking mechanism for locking an anchor belt reel to fix the seat against forward movement by the occupant restraint load.